A special system that is pipe connected to a source of foam concentrate and to a water supply. The
system equipped with appropriate discharge devices for extinguishing agent discharge and for
distribution over the area to be protected. The piping system is connected to the water supply
through a control valve that usually is actuated by operation of automatic detection equipment that
is installed in the same areas as the sprinklers. When this valve opens, water flows into the piping
system, foam concentrate is injected to the water, and resulting foam solution discharging through
the discharge devices generates and distributes foam. Upon exhaustion of the foam concentrate
supply, water discharge follows and continious untill shut off manually. Systems can be used for
discharge of water first, followed by discharge of foam for a specified period, and then followed by
water until manually shut off. Existing deluge sprinkler systems that have been converted to the use
of aqueous film-forming foam or film-forming fluoroprotein foam are classified as foam-water
sprinkler systems.